The present invention relates to a device for generating a laser radiation and an associated fabrication method.
Many types of devices provided for generating a laser radiation include a box in which a gas having a population inversion is confined. Such a population inversion, in which a first “high” energy state is more populated than a second, lower energy state, is necessary for the stimulated emission to become the dominant radiation for a laser radiation to be emitted.
In order to obtain such a population inversion, it is necessary for the gas contained in the box to be stimulated by an outside energy source. In particular, a plasma is frequently maintained in the box through the application of a difference in potential between two electrodes of the box. Each electrode then covers a hole of the box and must therefore ensure both the electricity transfer and the sealing between the inside and the outside of the box.
The box is frequently made from glass or vitroceramic, which imposes significant constraints on it regarding the methods used to fasten the electrode to the box. In particular, an indium alloy is frequently used to stick the electrode to the box. However, such an alloy is sensitive to corrosion and must be isolated from the outside by a sealing gasket. Yet the stresses, in particular shear stresses, tend to deteriorate the seal, and therefore the alloy, during the lifetime of the device. This results in a loss of sealing and the contamination or loss of the inside gas.
During the laser emission, the generating device reaches high temperatures of up to 120 degrees Celsius (° C.). Thus, the generating device is subject to large-amplitude thermal variations between the usage periods and the idle periods.
Furthermore, it is difficult to separate two parts adhered with such an indium alloy, which makes the device difficult to maintain. A device is known from document WO03/023325 A1 for generating a laser radiation in which a glass ring is inserted between the electrode and the box. The ring is fastened by molecular adhesion to the box and with an indium alloy to the electrode. However, such a ring increases the total height of the relief formed by the electrode, which increases the bulk of the device and makes the latter even more sensitive to shear stresses.
Furthermore, connections by molecular adhesion and with an indium alloy are difficult to produce and highly sensitive to any damage of the affected surfaces. Yet the aforementioned device does not allow easy monitoring of the state of the surfaces involved in the connection between the ring and the box or the electrode. Here again, this results in a risk of deterioration of the device.